Furnace using forced draft



8 Sheets-Sheet 1 E. A. M ARTHUR FURNACE USING FORCED DRAFT Filed NOV.11, 1925 f 1 Z A r J f INVENTOR April 16, 192.

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April 16, 1929. E, A, N's-ARTHUR 1,709,800

FURNACE USING FORCED DRAFT Filed Nov. 11, 1925 8 Sheets-Sheet 3 v I 4k\\\\\\\\\l k\\\ I O 4 0 o v ATTORNEY April 16; 199. E. A. MARTHU'i,79,0

* FURNACE USING FORCED DRAFT Filed Nov. 11, 1925 a Sheets-Sheet 5INVENTOR Ap 16, .E. A. McAR'rHufi 1,709,800

. FURNACE USING FORCED DRAFT v gamed Nov. 11, 1925 a Sheets-Sheet. 6

INVENTOR T- %W 'I'rO NEY- m 9 E. A. MQARTHUR 1,7(j)9,800

FURNACE USING FORCED DRAFT Filed Nov. 11, 1925 a' g t v INVENTOR:

WITN

April 16, 1929. I McARTHUR 1,709,800

FURNACE USING FORCED DRAFIf Fil 1925 a Sheets-Sheet 8 0 -"Hl'U-lir h HMW T WWW Patented Apr. 1 1929.

UNITED STATES PATIENT OFFICE.

ELMER A. MCARTHUR, OF FLINT, MICHIGAN.

summon USING roncn'n nnarn I Application filed November 11, 1925sSerial'NofGBAOG.

This invention relates to improvements in furnaces which are providedwith force draft and stokers for supplying air and fuel thereto, thegeneral object of the invention being to provide means for automaticallycontrolling the amou ntof air and fuel supplied to the furnace whichkeeps the steam pressure constant and which also reduces thefconsumptionof fuel to the minimum;

A further Object of the invention is to provide manually operated meansfor regulating the o eration of the inventiominsuch' a manner t iatithesteam pressure canbe'raised or lowered, as,desired. I

A further object of the invention is to provide means for co rct'mg theunburnt gases in the furnace and returning them to the fire box.

Another object of the invention is to make the furnace operate with butlittle attention 'on the part of the firemen, so that one fireman cantake care of a battery of furnaces when necessary. I H

This invention also consists incertain other features of constructionandin the combination and arrangement-"of the several parts, to I behereinafter fully described, illustrated in v in use.

the accompanyingdrawings and specifically. pointed out in theappendedclaims. I

In describing myinvention in detail-{retenence will be had to theaccompanyingfdr'awings wherein like characters denote like or Figure 6is a similar view,-but showing the wedge member and its operatingmean'siri lowered position. v

Figure 7 1s a section on line 77 of Figure 5.

Figure 8 is an enlarged View, with parts in section, of the.,.stea'mactuated means for automatically controlling the air blast.

Figure 9 is a sectional view througlrthe Figure 4 is a section on line4-4 of Fig- I rear part of a furnace, showing the gas collecting means.

collecting means. I I

Figure 11 is an enlarged View partly in section of the stoker and theoperating parts associated therewith.

Figure 10 is a sectional view taken at right angles to Figure 9, andshowing the gas" In these drawings, 1 "indicates the grate of thefurnace upon which coal is pushed from the chute 2 by the stoker 3, theram 4 of which is located in the horizontal part of the chluteand thepusher rod of which is shown at 4. The drawings show the Jones type ofstoker, thoughit will be understood that any other type may be used. Theair blast apparatus is shown at 5 and is arranged below is arrangedunder the grate aiid in which is located my valve or bafile forcontrdlling the amount of air passing through the grate. It'w'ilLbenoted that the, inner end of the grate is lower than theouter end. Thisvalve or baflle comp-rises a shaft 8 journaied in the chambei 'f andhaving secured thereto the disks 9, an upper wing and the lower wing11.- .These wings are' -m'ovably connected with the shaft and the upperwing is adjustably connected with the disks by means of the .the floor 6of the boiler room. This apparatus delivers the air into the chamber 7which j slot and boltconnection shown generallyat t; 12, while the"lower wing is adjustably con f nected with the u'pper wing by means ot'thef I: two pairs of links 13, the links of each pair being connectedtogether by the bolt and slot connections, shown enerally at14.' Thusthe upper wing. can e adjusted relative to v the shaft and-its'disk andthe lower wing can be adjusted relative to the upper wing. The

upperwing, when in its raised position, will 9 have its beveledendengage a plate whichis arranged under a number of thegrate bars of grate1, the spaces between which are filled, as shown at 1. The upper wing isprovided with anopening 10 which is adapted to be closed by a flap l6adjustably connected tea.

fiap' 17 hinged to the: end of the lower wing 11 by means of the twopairs of links 18, the links .of each pair being adjustably connectedtogether by the bolts and slots, shown generally lower wing and thesesprings are connected with the flap 16 by the connections 21 whichinclude the turnbuckles 21, the springs tending to hold the valve 16inopen position at r s are nnec ed with the These parts are so arrangedthat when in lowered position, the lower wing will cover the outlet ofthe blast apparatus so that when position, the device will cause most ofthe air to. pass through the inner portion of the grate, Where the barsare spaced farther .apart than are the bars of the rest of the grate.Thus the green fuel which has just been pushed on to the grate by thestoker is subjected to but littledraft, so that it will gradually cokeand the gases from the same be consumed in the fire box, while the fuelon the inner or rear part of the grate which has been coked will besubjected to the major portion of the blast and thus be consumed withthe minimum amount of waste. .If the blast is at its maximum, thepressure against the lower flap 17 will swing the same inwardly andupwardly and thus cause the flap 16 to close the opening 10' in theupper wing and thus reduce the amount of air reaching the fuel on theouter part of the grate.

In order to make the operation of the furnace practically automatic, Iprovide means for controlling the amount of the air entering chamber 7to act on the bafiie or valve by means of the steam pressure in theboiler. Such means comprises a damper 5 in the air passage of the blastapparatus 5 which has a gear 22 on its stem which meshes with a gear-23,rocked on a shaft by the movement of a segmental ear 24 whichisconnected with the gear 23 by the connections 25. Gear 24 meshes with asimilar gear 26 which is provided with a stem 27 to which a weight 28 isadjustably connected. These parts are arranged on a frame 29 which maybe located in a pit in the floor of the furnace room. A cylinder 30 isarranged in said pit and is connected with the frame and its piston 31has its rod 32 provided with two rollers 33 which receive the stem 27between them, so that the stem must movewith the piston. A steam cushionline 34 isconnected with the upper part of the cylinder and contains avalve 35 and a pipe line 36 connects the lower part of the cylinder withthe boiler. A sliding valve casing 37 and a rotary valve casing 38 arearranged in the line 36. A valve 39 in casing 38 is operable by thelever 40 pivoted to a link 41 and connected to the arm 42 of the valveand said valve is provided with the passage 43 which is designed toregister with either the upper port 44 on the lower port 44' in theinlet end of the casing 38 and the branch passage 43 which is adapted toconnect the passage 43 with the exhaust 45 of the casing 38.

A'slide valve 46 is arranged in the casing 37 and has its single port 47arranged to register with either the port 48 or the port 48' in saidcasing. This valve has a spring 49 on its stem which tends to hold thevalve with its port in register with the port 48 and a rod 50 ispivotally connected with the other end of the stem in the valve. Thisrod has its other end pivotally connected to a forked member 51 whichpasses through a hole in an arm 52 on the gear 24, a coiled spring 53being arranged on the member 51 between the arm 52 and a nut 54 on saidmember. The pin 55 which connects the rod 50 with the member 51 passesthrough a curved slot 26 in the gear 26 and said rod 50 is provided witha pair of notches 50. A slide 56 is arranged in a guideway 57 on frame29 and carries a projection 58 which is adapted to engage either one ofthe notches 50. The slide carries a roller 59 which is pressed against acam part 60 on gear 26 by a spring 61 engaging the upper end of theslide.

When the pressure of steam in the boiler is at its highest point, theaction of the steam on the piston 31 will have moved the weighted stem27 of gear 26 to its highest point, and this movement of the gear 26will act on the gear 24 and this movement of the gear 24 will becommunicated to the pinion 22 of the damper of the blast apparatusthrough the connections 25 and gear 23 to close the same, so that thedraft will be reduced to a minimum. As soon as the pressure, falls,however, the weighted stem 27 will move downwardly under the action ofgravity and also by the action of the cushion of steam in the upper partof the cylinder and in the pipe 84, acti ng on the piston 31 so thatthe, gears 26 and- 24 will move upwardly to open the damper to increasethe draft and during this action the arm 52 will compress the spring 53until it is stronger than the spring 49, so that said spring 53, actingon the rod 50, which has been released by the projection 58 being movedupwardly out of the notch through the engagement of the roller-59 by thecam 60, will move the rod 50 and the valve 46 to the left in F igure8,-thus closing the port 48 and shutting off the supply of steam to thecylinder 30. This movement of :rod 50 is communicated to the lever 40which is connected with the rod by the pin .and slot connection 62 sothat the valve 39will be moved'until the branch 43 of its passage is inregister with the exhaust 45 of the casing 38 and the inlet end ofpassage 43 is out of register with the inlet I der the movement of theparts, it will move rod 50 again and place the port 47 of valve 46 inregister with the port 48' in casing 37 and this further movement willvalso move valve 39 to close the exhaust and place the second notch 50 insaid rod 50 and locked the parts against further movement. As the steampressure in the boiler rises under the increased draft by the opening ofthe valve or damper in the blast apparatus, the )ressure of steam incylinder 30 will gradua ly overcome the weight 28 and the steam cushionin pipe 34 and thus raise the stem 27 and cause the gears :24 and 26 tomove downwardly and partially closethe damper. Under this action, thespring 53 will lose some of its tension and the projection 58 will moveout of the inner notch 50 as the roller on the slide moves over the cam60, so that the spring 49 will snap the valve and the rod 50 to theirfirst posi' tion and place the port 47 in the valve in register withport 48 so that the steam will continue to pass to the cylinder 30, butthrough port 48 instead of port 48. The parts will be locked in thisposition by the downward movement of theslide and the engagement of theprojection 58 in the outer notch 50. The movement of the rod 50, un derthe action of the spring 49, will move the plug 39 to its firstposition, as shown in Figure 8. Thus the steam pressure in the boilerwill remain constant and in order to place the pressure at any desireddegree, we provide a hand lever 63 which is connected by link 64 withthe handle 65 of the cushion regulating valve 35 in pipe 34. The handleis connected by a link 66 with the handle 67 of a valve 68 whichregulates the size of the outlet port 45 of casing 38. By moving thehandlever to the desired degree on a scale associated with the lever,the steam pressure in the boiler can be held at the desired pressure.

As before stated, the baffle device in chamher 7 will be raised orlowered according to the amount of pressure of the air coming from theair blast apparatus and this will also help to automatically control thesteam pressure in the boiler and in addition, the movement of the bafilewill act to adjust the damper in the chimney of the furnace throughmeans of an arm 68 on shaft 8 which is connected with the damper by theconnection 69, so that the movement of the shaft 8 will be communicatcdto the damper in the chimney and thus further control the draft.

The baflle device is also used to regulate the stroke of the stoker soas to control the amount of fuel fed upon the grate bars. Such meansconsist of a lever 70 pivoted to the floor 6 and having an adjustableforked part 71 which is engaged by a pin 72 on one of the disks 9, sothat when the disk is moved to a certain extent, the pin engaging thevalve stems to each other.

forked part will rock the lever 70 on its pivot, and this movement iscommunicated to a lever 73 by a turnbuckle rod 74 which is connectedwith a bell crank 75 on the lever 73 so that the lever 73 is not onlymoved but its latch 73 is also actuated by the movement of the lever 70.The latch 73 is adapt ed to engage a notch of a segmental rack 118 formaintaining the parts associated with the levers 73 in a predeterminedposition until said latch is released. An arm 76 is connected with theshaft to which the lever 73 is connected and this arm has a roller 77 onits free end which engages a plate 78 pivoted to the block 7 9 carriedby the fixed rod 111, said block 79 having a slot 80 therein whichreceives a pin 81 on the depending arm 82 of the ram of the stoker. Theplate 78 engages a wedge 83 which is slidably mounted in a slot 79"formed in the block 79. A pin 84 secured to the wedge and movable in aslot 80 of the block, guides the wedge in its movement. The parts are soarranged that as the plate 78 is forced upwardly by the arm 76, it willmove the wedge upwardly and thus prevent the pin 81 on arm 82 reachingthe outer end of the slot 80 and thus the stroke of the stoker isshortened and less coal is pushed upon the grate bars. The pin 81 notonly guides the lower end of the arm 82, but in conjunction with the endof the slot 80 limits the movement of the arm.

I also provide means for reclaiming some of the roducts of combustion,such means comprising a chamber 84 arranged over a passage 85' whichconnects the chimney 86 with the major portion of the furnace andbafiles 87 are arranged in the bottom of the chamber and extend into thetop of the passage so that the lighter particles of the gases passingthrough the passage 85 will be di rected into the chamber by thesebaffles. The passage of the gases into the chamber is controlled by thevalves 88, all of which are manually controlled through-the, chain 89.the double lever 90 connected with one of the valve stems and to whichthe chain is connected and the links 91 which connect the A weightedgate 92 controls an air opening 93 in one end of the chamber and achamber 94 having a fan 94 or other suction producing device is incommunication-with the other end of the chamber 84 The flat valve 92controls the amount of air passing into the conduit 84, and the openingof said valve depends upon the speed of rotation of the fan 94.Therefore the valve 92 controls the proper quantity of air to besupplied to the products of combustion for a complete burning of saidproducts. A pipe line 95 connects the outlet of the chamber 9-1- with apipe 96 which extends into thev combustion chamber of the furnace sothat the reclaimed gases will be discharged into through the line 95 bythe valve or baflie de vice in chamber 7. Such means consists of a gear97 on the stem of a damper in said line 95 and which meshes with a gear98, the

shaft of which is connected with an arm 99 to which a link 100 isadjustably connected, the other end of the link being adjustablyconnected with one of the disks 9 through means of, the slot and boltconnection 101.

A damper 97* is rigid with the shaft of gear 97 From the foregoing, itwill be seen that the air blastdevice is controlled by the steampressure in the boiler so that this device will be actuated to maintaina constant pressure in the boiler, the pressure desired being setthrough the hand lever 63. The valve or baifle device in chamber 7 alsoacts'in conjunction with the air device to automatically control thepressure through its draft con-v trolling properties, the damper in thechimney, the changing of the stroke of the stoker and its control overthe damper in the reclaimed gas line. As before stated, the said devicein chamber 7 also insures the proper combustion of the fuel through thecontrol of the draft to the green or fresh fuel. The operation of thisapparatus, when applied to a furnace, is practically automatic and needsbut little attention on the part of the firemen, so that the one firemancan look after a greater number of furnaces provided with my inventionthan he could if the furnaces were not provided with the invention.

It is thought from the foregoing descrip-v tion that the advantages andnovel features of my invention will be readily apparent.

I desire'it to be understood that- I may make changes in theconstruction and in the combination and arrangement of the severalparts, provided that such changes fall within the scope of the appendedclaims. A block 7 9 is supported by a rod 111 which has one end securedto said block and the'other end carried by a wall 112 of the furnace.The push rod 4 mounted in the cylinder which formspart of the operatingmeans of the stoker has a piston 110 mounted therein actuated by steamor compressed air for actuating the ram at at the bottom of the chutewhere the ram 4* slides over the same. The bottom of the chute 2 has anopening over which the ram .4 slides when moving the coal onto the grate1 and through which is adapted to be moved the arm 82 which is connectedwith the ram 4 and which is adapted to be engaged by the wedge 83 forlimiting the outward movement of the ram and tl1crcby controlling thestroke of said ram,

At the rear of the furnace achamber 120 is shown in which the watertubes 121 are extended and adjacent the passage 85. A wall ing means 89for the baflles 87.

"What I claim is 1. In a furnace, a steam boiler, a grate, in

heating relation with the boiler, an air passage in communication withthe grate, an air blast device in communication with the air passage,means for controlling the air blast in response to the steam pressure inthe boiler, a baffle for controlling the draft to the green fuel on thegrate of the furnace, and means actuated by the draft for mvoing thebattle to controlling position. 1 I

2. In a furnace, a steam boiler, a grate in heating relation with theboiler, an air passage in communication with the grate, an air blastdevice in communication with the air passage, means for controlling theair blast in response to the steam pressure in the boiler, a battle forcontrolling the draft to the green fuel on the grate of the furnace,means actuated by the draft for moving the baffle to controllingposition, a stoker having a reciprocating ram, and means actuated by themovement of the baflle for controlling the strokes of the ram. I

3. In a furnace, a steam boiler, a grate in heating relation with theboiler, an air passage in communication with the grate, an air blastdevice in communication with the air passage, means for controlling theair blast in response to the steam pressure in the boiler, a baflie forcontrolling the draft to the green fuel on the grate of the furnace,means actuated by. the draft for moving the battle to controllingposition, manually operated means associated with the controlling meansfor the blast apparatus foradjustin'g the controlling means to hold thesteam pressure at any desired degree.

1-. In a furnace, a steam boiler, a grate in heating relation with theboiler, an air passage in communication with the grate, an air blastdevice in communication with the air passage, means for controlling theair blast in response to the steam pressure in the boiler, a battle forcontrolling the draft to the green fuel on the grate of the furnace,means actuated by the draft for moving the baflie to controllingposition, means for reclaiming the unconsumed gases passing from thefurnace and introducing them at a point above the grate, and means forcontrolling the flow of such gases.

5. In a furnace, a steam boiler, a grate in heating relation-with theboiler, an air passage in communication with the grate, an air blastdevice in communication with the air passage, means for controlling theair blast, in response to the steam pressure in the boiler,

a bafiie for controlling the draft to the green fuel on the grate of thefurnace, means actuated by the draft for moving the battle tocontrolling position, means for reclaiming the loo unconsumed gasespassing from the furnace and introducing them at a point above thegrate, means for controlling the flow of such gases, and meansoperatively connected with the battle for operating the controllingmeans for the gases.

6. In a furnace, a grate, an air blast apparatus, means leading from theair blast appa ratus to the grate, a swinging baflle for controlling theflow of air through the grate, said baflle comprising an upper wing anda lower wing ad justably connected together, the lower wing beingpositioned to be acted upon by the blast to move the battle,the upperwing having an opening therein, a. movable fia p for covering theopening, a movable flap on the lower wing, and means for adjustablyconnecting the two flaps together, the last mentioned flap beingpositioned to be acted on by the blast to move the first mentioned flapto closing position.

7. In a furnace, a grate, an air blast apparatus, means leading from theair blast apparatus to the grate, a swinging battle for controlling theflow of air through the grate, said baffle comprising an upper wing anda lower wing adjust-ably connected together, the lower wing beingpositioned to be acted upon by the blast to move the baflie, the uperwing having an opening therein, a movable flap for covering the opening,a movable flap on the lower wing, means for adj'ustably connecting thetwo flaps together, the last mentioned flap being positioned to be actedon by the blast to move the first mentioned flap to closing position,and spring means for holding the upper flap in open position.

8. In a furnace, a grate, an air blast device, an air passage placingthe grate in communication with the air blast device, 'a ram adapted tobe actuated for stoking the furnace and provided with a. depending arm,a swinging baflie for controlling the passage of air to the grate, andacted on by air from the air blast device for causing swinging of thebattle, a lever rocked by the movementof the baflle, a second lever,means for moving the second lever by the movement of the first lever, anarm actuated by the second lever, a wedge member movable by the arm andengaging the depending arm of the ram for varying the reciprocatingmovement of said ram, a block slidably supporting the Wedge member andhaving a slot therein, and a pin on the arm which depends from the ram,said pin being received within the slot for guiding the arm in itsmovements.

9. In a furnace, a grate, a swinging battle for controlling the draft tothe grate and comprising a shaft, a pair of discs on the shaft, upperand lower wings movably connected with the shaft, means for adjustablyconnecting the upper wing with the discs, means for adjustablyconnecting the lower wing with the upper wing, the lower wing beingpositioned to be acted upon by the blast to move the battle, said upperwing having an opening, a movable flap for closing said opening, aspring for holding said flap in open position, a second movable flaphinged to the lower wing, means for connecting the flaps together, thelast mentioned flap being positioned to be acted on by the blast to movethe first mentioned flap to closing position, and a cross piece on thegrate adapted to be engaged by the upper wing for limiting the movementof said wing.

10. In a furnace, a grate, an air blast device, an ash pit for placingthe air blast de vice in communication with the grate, a baffleswingably mounted in the ash pit and adapted to be moved to an operativeupper position relative to the grate by the air from the air blast forcausing the air to be forced through the inner end of the grate, saidbafile when in a normal inoperative and lower position permitting theair topass to all parts of the grate.

11. In a furnace, a grate, an ash pit located below the grate, aswingably mounted battle in the ash pit, an air blast device, said pitplacing the air blast device in communication with the rate, said bafilecont-rolling the direction o' the path of movement of the air from theair blast device to the grate and to various parts of the grate, saidbafiie being provided with an opening to normally permit the passage ofair therethrough, a hingedly mounted flap carried by the baffle forclosing the opening and means carried by the baflie and adapted to beactuated by the air blast for closing said opening, said actuating meansincluding a movable flap adjustably connected with the first-mentionedflap whereby actuation of this second-mentioned flap by the air blastcauses closing movement of the first mentioned flap. In testimonywhereof I affix my signature.

ELMER A. MoARTI-IUR.

